Systems, methods, and devices for wireless charging

ABSTRACT

Embodiments relating to systems, methods, and devices for wireless charging are disclosed. In some embodiments, methods for establishing a communication link between a power transmitting unit (PTU) and a power receiving unit (PRU) through a low energy wireless communication interface are described.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional PatentApplication Ser. No. 62/018,385, filed on Jun. 27, 2014, the disclosureof which is incorporated herein by reference.

TECHNICAL FIELD

Embodiments described herein generally relate to transferring powerbetween devices.

BACKGROUND

Wireless power transfer may include wirelessly or inductivelytransferring power via non-radiative, near-field magnetic resonance. Insome examples, wireless power transfer may be defined as a resonantwireless transfer of power through magnetic induction between coilslocated at a power transmitting unit (PTU) and coils located at a powerreceiving unit (PRU). The transferred power received at the PRU mayenable wireless charging of a battery for various types of portabledevices such as headsets, smart phones, portable game or media players,game controllers, tablets, netbooks, notebooks, wearable computerdevices, etc. However, when there are multiple PTUs and multiple PRUs inthe same area, a problem called “cross connection” may arise. Forexample, two or more PTUs may try to wirelessly charge the same PRU atthe same time. Namely there may be a possibility of a local PRU toconnect to a PTU in a remote location by mistake due to inherent longrange nature of BLE radio, and because the remote PTU grabs the PRU overthe Bluetooth low energy (BLE) control channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless charging system, accordingto one example embodiment;

FIG. 2 illustrates an architecture of a wireless charging system,according to one example embodiment;

FIG. 3 illustrates an example of a wireless charging system, accordingto one example embodiment;

FIG. 4 illustrates the operation and timing of a PTU and PRU, accordingto one example embodiment;

FIG. 5 illustrates an example block diagram for an apparatus, accordingto one example embodiment;

FIG. 6 illustrates an example of a logic flow, according to one exampleembodiment;

FIG. 7 illustrates an example of a storage medium, according to oneexample embodiment; and

FIG. 8 illustrates an example of a device, according to one exampleembodiment.

DETAILED DESCRIPTION

Embodiments presented herein are generally directed to systems, methods,and devices for wireless charging. Recent collaborative efforts todevelop standards for wireless charging have led to multiple wirelesscharging standards such one approved by the Alliance for Wireless Power(“A4WP”). An example wireless standard approved by A4WP is “Version 1.0Baseline System Specification (BSS)”, published in January 2013 (“theA4WP standard”). The A4WP standard is based on impedance/load detectionand use of Bluetooth® low energy (BLE) advertisements (ADVs). BLE ADVsmay be generated by circuitry at a power receiving unit (PRU) inaccordance both the A4WP standard and/or the Bluetooth Specification,Version 4.0, published in June 2010 and/or later versions or revisions(“the BLE standard”). Impedance/load detection and use of BLE ADVsaccording to the A4WP standard may determine a relationship (e.g.,relative locations) between the PTU and one or more power receivingunits (PRUs). Due to some inherent difficulties associated withimpedance/load detection and BLE ADV received signal strength indicator(RSSI) fluctuation, it may be difficult to determine which PRU undercharge is powered by the PTU. An occasional cross connect may occur thatresults in the PTU connecting to a remote PRU that may be within BLE ADVrange but not physically located close enough for wireless charging. Itis with respect to these and other challenges that the examplesdescribed herein are needed.

Embodiments of the present disclosure provide numerous technical effectsand unobvious solutions over conventional solutions. For example,according to some embodiments, certain methods may be implemented at aPTU. For these embodiments, the PTU may be capable of inductively orwirelessly transferring power to one or more PRUs. The PTU may detect afirst PRU based on use of a transmitted short beacon (e.g., a A4WP shortpower beacon) to detect an impedance or charging load associated withthe first PRU. Also, for these examples, a long beacon (e.g., a A4WPlong power beacon) may be transmitted that includes a modulatedsignature in the long beacon. The long beacon may cause the first PRU toenergize a low energy wireless communication interface (e.g., a BLEinterface). Also, for these examples, the energized low power interface(BLE) may transmit an advertisement (ADV) packet from the first PRU. Aconnection request may then be sent to establish a communication linkwith the first PRU through the low energy wireless communication link ifthe ADV packet includes a signature that matches the modulatedsignature. The PTU may transition to the next power state to keeppowering the first PRU while maintaining the communication link.

According to some other embodiments, certain methods may be implementedat a PRU. For these other embodiments, the PRU may receive a long beacon(e.g., A4WP long power beacon) that includes a modulated signature thatidentifies a PTU capable of inductively or wirelessly transferring powerto the PRU. A low energy wireless communication interface (e.g., BLEinterface) may be energized responsive to receiving the long beacon. Themodulated signature may be decoded and an ADV packet may be generatedthat includes the decoded signature. Also, for these other examples, theADV packet may be transmitted, after which the PTU may establish acommunication link with the PRU through the low energy wirelesscommunication interface. The PTU may transition to the next power statefor PRU to charge and maintain the communication link.

FIG. 1 illustrates an example system according to at least oneembodiment. In some examples, the example system includes system 100.System 100, as shown in FIG. 1, includes a power transmit unit (PTU) 110to interact with one or more power receive units (PRUs) 120-1 to 120-n,where “n” is any positive integer greater than 1. According to someexamples, power links 112-1 to 112-n and communication links 114-1 to114-n may allow for physical and functional interactions between PTU 110and PRUs 120-1 to 120-n. The physical interaction may include PTU 110wirelessly or inductively transferring power to any one of PRUs 120-1 to120-n via respective power links 112-1 to 112-n. The functionalinteraction may occur over communication links 114-1 to 114-n and logicand/or features of PTU 110 or PRUs 120-1 to 120-n may be capable ofconducting such functional interactions as session or power controlmanagement through lower power wireless communication interfaces overthese communication links.

FIG. 2 illustrates another example system. In some embodiments, theexample system includes system 200. System 200 as shown in FIG. 2includes a PTU 210 and a PRU 220. According to some examples, PTU 210and PRU 220 may be configured in compliance with one or more standardsfor wirelessly or inductively charging a device load such as the A4WPstandard.

In some embodiments, as shown in FIG. 2, PTU 210 includes a transmitresonator 211, a matching circuit 213, a power amplifier 215, a powersupply 217 or a lower power wireless communication interface 219. Also,as shown in FIG. 2, PRU 220 includes a receive resonator 221, arectifier 223, a direct current (DC) to DC 225, a device load 227 or alower power wireless communication interface 229. For these embodiments,transmit resonator 211 may be capable of wireless power transfer viaresonate coupling to receive resonator 221 at an operating frequency inthe industrial, scientific and medical (ISM) radio band that mayinclude, but is not limited to, 6.78 megahertz (MHz). Power supply 217may supply the power, power amp 215 may adjust the power to be providedand matching circuit 213 may match impedance to assist with the powertransfer from transmit resonator 211. Also, for these embodiments,rectifier 223 may be used to convert the power received via receiveresonator 221 from an alternating current (AC) to a direct current (DC),DC to DC 225 may assist in providing a DC load to device load 227.

According to some embodiments, control information to facilitatewireless power transfer may be exchanged between PTU 210 and PRU 220over communication link 230. For these embodiments, lower power wirelesscommunication interface 219 of PTU 210 and lower power wirelesscommunication interface 229 of PRU 220 may be configured or arranged tobe operated by logic or features of circuitry 218 and 228, respectively,according to the BLE standard. Circuitry 218 or 228 may be capable ofsending packets through lower power wireless communication interfaces219 or 229 and over communication link 230 using a management protocolaccording to the A4WP standard or the BLE standard. As described morebelow, this may include the use of BLE ADV and connection requestpackets.

FIG. 3 illustrates a problem called “cross connection” that may arisewhen there are multiple PTUs and multiple PRUs in the same area. Forexample, as illustrated in FIG. 3, two or more PTUs 110, 116 may try towirelessly charge the same PRU 120-1 at the same time. Namely there maybe a possibility of a local PRU 120-1 to connect to a PTU 116 in aremote location by mistake due to inherent long range nature of BLEradio, and because the remote PTU 116 could grab the PRU 120-1 over theBluetooth low energy (BLE) control channel. For example, remote PTU 116can establish a connection with PRU 120-1 over communication link 119-1merely due to the BLE. The power link 118-1 may not be able to power PRU120-1. The result is that PTU 110 does not establish communication link114-1 and turn off the power link 112-1, and PRU 120-1 does not receiveany more power.

Certain technical effects or solutions can be accomplished by certainembodiments of the disclosure, for example, certain embodiments ofsystems, methods, and devices described herein can provide for a forwardsignaling protocol and format for low cost, high efficiency, and robustimplementation. One example embodiment is illustrated in FIG. 4, whichillustrates one example of a wireless communication protocol between aPTU 110 and PRU 120-1. According to this example embodiment, themodulation may be initiated by the PTU 110 upon the detection of BLEadvertisement (ADV) packets from PRU 120-1. The BLE ADV is sent by thePRU 120-1 that receives an initial, low charging power for setting up aBLE connection. The initial BLE ADV packet in FIG. 4 indicates that thePRU 120-1 supports forward signaling capability and no message about PTUID is received. This is an indicator that PRU 120-1 is looking forwardto connecting to a local PTU 110.

In the next operation, for example, the PTU 110 sends a message to thePRU 120-1 by modulating the power to the PRU 120-1. Namely, the messagesignal rides on the charging signal, for example. The message caninclude a sequence of information bits, for example. The message mayalso be encoded, for example. The encoder outputs a sequence of codebits. The encoder may be a convolutional encoder and the code bits maybe further spread as in CDMA system, for example. In general, a sequenceof information bits is mapped to a longer sequence of code bits forsubsequent modulation.

After encoding/spreading, the modulation of the code bit sequence can bebinary phase shift keying (BPSK), for example. The charging powerreceived at the PRU 120-1 can fluctuate suddenly due to various reasonse.g., load change at PRU 120-1 or other PRU 120-n or supply change atPTU 110. The fluctuation can interfere with the BPSK reception. In orderto enhance the detection reliability and to enhance reliability of themessage, differential modulation may further be applied. For example,the BPSK modulated sequence can be 1, −1, −1, 1. The differentiallymodulated sequence can then be 1, 1, −1, 1, 1. This allows the receivere.g., PRU 120-1 to detect the code bit sequence using the received powerlevel of the previous code bit as reference. Since the message signalrides on the charging signal, the magnitude of the message signal isusually much smaller than that of the charging signal. For example, themagnitude of the message signal is typically about 5% or less of that ofthe charging signal. The modulation may typically be a fixed voltageswing, for example, 0.5V at all power levels.

Since the magnitude of the received message signal can be used todetermine the distance/coupling between the PTUs and PRU 120-1 such thatthe PRU 120-1 can pick the closest PTU 110 for high charging efficiency,it is desirable the transmitted magnitude of the message signal be thesame for all PTUs. The PRU 120-1 may receive multiple message signalsfrom multiple PTUs and decode the strongest message for connecting tothe closest PTU 110. This allows the PRU 120-1 to find the closest PTU110 even if different PTU use different charging voltages. For detectingthe message, the PRU 120-1 needs to know when the PTU 110 starts to sendthe message.

In certain embodiments, the timing of the PRU/PTU operations can be setby the advertisement (ADV) packet. The transmit/receive time of themodulated message may be aligned with the BLE timing. For example, therecan be three BLE advertisement channels. The PRU 120-1 sends ADVs on allthree advertisement channels sequentially. Therefore, the PTU 110 andthe PRU 120-1 need to determine the actual start time of the modulatedmessage from the ADV and the advertisement channel ID. For example, theBLE ADV may specify the start time of the message sent by the PTU 110.As another example, a transmission delay may be predefined for eachadvertisement channel. For example, if the ADV is received from channel1, then the start time of message transmission is about 500micro-seconds after the termination of the ADC on channel 1. As yetanother example, the termination of advertisement event can bedetermined in BLE regardless of the advertisement channel used.Therefore, the termination time of the advertisement event can be usedas a timing reference point.

After the first ADV packet in FIG. 4 is sent, the PRU 120-1 expects thatthe message will arrive within a time interval that can be determined.Similarly, the PTU 110 receives the ADV should send message asdetermined by ADV or/and advertisement channel ID or/and otherparameters in the standard. The modulated signal is aligned with the ADVpacket timing, for example, the modulation begins a fixed or known timeafter the reception of the ADV packet. This may enable the PRU 120-1 todetect and to time synchronize.

In the next operation, for example, the PRU 120-1 decodes the messageand sends it by the next ADV packet in the ID field. If PTU 110 receivesthe next ADV packet with a matching ID to the message, it sends theconnect_req and transitions to next A4WP power state, for example.

Turning now to FIG. 6, a method of wireless charging communication 600is illustrated, according to one example embodiment. According to thismethod 600, in operation 610, the PRU 120-1 sends ADV with forwardsignaling support bit and empty ID field. In operation 620, the PTU 110detects the ADV and determines the message transmission time accordingto the methods and systems described above. In operation 630, PTU 110starts power modulation after a (fixed or varying) timing delay.Modulation can be a differential CDMA/convolutional code AM modulation,as described in the above embodiments. In operation 640, the PRU 120-1can decode the message, for example, and in operation 650, the PRU 120-1sends ADV (with forward signaling support bit) and ID extracted from themessage received from the PTU 110. In operation 660, the PTU 110 detectsthe ADV with matching ID and sends a conn_req, and transitions to thenext A4WP power state, for example.

Certain technical effects or solutions can be accomplished by certainembodiments of the disclosure, for example, certain example embodimentsdescribed herein may be that the combination of time sync with anexternal radio for inline power communication saves on signal designcomplexity. Differential signaling is robust against power lineimpairment. Additionally, CDMA or convolution coding/encoding is robustagainst noise and very simple to implement on the MCU.

Although example embodiments described herein involve two or more PTUs,and one or more PRUs, the methods and systems described herein can beapplied any combination of PTUs and PRUs. Although the modulation ofpower in long beacon is discussed herein, the modulation may beapplicable in power transfer state when continuous power transfer ishappening, for example, when the PTU is already charging a PRU 120-1,and a new PRU 120-2 is placed on the PTU. It should be appreciated thatthe above examples of technical effects and/or solutions of the presentdisclosure are merely illustrative and that numerous other technicaleffects and/or advantages may exist.

FIG. 5 illustrates a block diagram for an example apparatus, which maybe any one of the PTUs or PRUs described above, according to at leastone embodiment of the disclosure. As shown in FIG. 5, the apparatusincludes an apparatus 500. Although apparatus 500 shown in FIG. 5 has alimited number of elements in a certain topology or configuration, itmay be appreciated that apparatus 500 may include more or less elementsin alternate configurations as desired for a given implementation.

The apparatus 500 may include a component of a PTU (e.g., PTU 110) thatmay be firmware implemented and have a circuitry 520 arranged to executeone or more components 522-a. It is worthy to note that “a” and “b” and“c” and similar designators as used herein are intended to be variablesrepresenting any positive integer. Thus, for example, if animplementation sets a value for a=6, then a complete set of components522-a may include components 522-1, 522-2, 522-3, 522-4, 522-5 or 522-6.The examples are not limited in this context.

In some embodiments, as shown in FIG. 5, apparatus 500 includescircuitry 520. Circuitry 520 may be generally arranged to execute one ormore components 522-a. Circuitry 520 can be any of various commerciallyavailable processors, including without limitation an AMD® Athlon®,Duron® and Opteron® processors; ARM® application, embedded and secureprocessors; IBM® and Motorola® DragonBall® and PowerPC® processors; IBMand Sony® Cell processors; Qualcomm® Snapdragon®; Intel® Celeron®, Core(2) Duo®, Core i3, Core i5, Core i7, Itanium®, Pentium®, Xeon®, Atom®and XScale® processors; and similar processors. Dual microprocessors,multi-core processors, and other multi-processor architectures may alsobe employed as circuitry 520. According to some examples circuitry 520may also be an application specific integrated circuit (ASIC) andcomponents 522-a may be implemented as hardware elements of the ASIC.

According to some embodiments, apparatus 500 may include a detectcomponent 522-1. Detect component 522-1 may be executed by circuitry 520to detect a first PRU based on use of a transmitted short beacon todetect an impedance or charging load associated with the first PRU. Forthese embodiments, the transmitted short beacon may be included in shortbeacon(s) 505 and detection may be included in impedance information510.

In some embodiments, apparatus 500 may also include a signaturecomponent 522-2. Signature component 522-2 may be executed by circuitry520 to generate a signature. For these embodiments, the signature may berandomly generated by signature component 522-2.

According to some embodiments, apparatus 500 may also include a beaconcomponent 522-3. Beacon component 522-3 may be executed by circuitry 520to transmit a long beacon that includes a modulated signature in thelong beacon for the signature generated by signature component 522-2.The long beacon may cause the first PRU to energize a low energywireless communication interface (e.g., BLE interface). For theseembodiments, the long beacon may be included in long beacon 515.

In some embodiments, apparatus 500 may include a receive component522-4. Receive component 522-4 may be executed by circuitry to receivean ADV packet from the first PRU. For these embodiments, the ADV packetmay have been included in ADV packet(s) 535.

According to some embodiments, apparatus 500 may include a connectioncomponent 522-5. Connection component 522-5 may be executed by circuitry520 to send a connection request to establish a communication link withthe first PRU through the low energy wireless communication interface ifthe ADV packet includes a signature that matches the modulatedsignature. For these embodiments, the connection request may be includedin connection request 540.

In some embodiments, apparatus 500 may include a transfer component522-6. Transfer component 522-6 may be executed by circuitry to causepower to be transferred to the first PRU while maintaining thecommunication link. For these embodiments, control information 545 mayinclude management or control information to facilitate wireless orinductive power transfer to the first PRU.

Included herein is a set of logic flows representative of examplemethodologies for performing novel aspects of the disclosedarchitecture. While, for purposes of simplicity of explanation, the oneor more methodologies shown herein are shown and described as a seriesof acts, those skilled in the art will understand and appreciate thatthe methodologies are not limited by the order of acts. Some acts may,in accordance therewith, occur in a different order and/or concurrentlywith other acts from that shown and described herein. For example, thoseskilled in the art will understand and appreciate that a methodologycould alternatively be represented as a series of interrelated states orevents, such as in a state diagram. Moreover, not all acts illustratedin a methodology may be required for a novel implementation.

A logic flow may be implemented in software, firmware, and/or hardware.In software and firmware embodiments, a logic flow may be implemented bycomputer executable instructions stored on at least one non-transitorycomputer readable medium or machine readable medium, such as an optical,magnetic or semiconductor storage. The embodiments are not limited inthis context.

FIG. 7 illustrates an embodiment of an example storage medium, which maybe embedded in a component of PTU (e.g., PTU 110) or a component of aPRU (e.g., 120-1), according to at least one embodiment of thedisclosure. As shown in FIG. 7, the storage medium includes a storagemedium 700. Storage medium 700 may include an article of manufacture. Insome embodiments, storage medium 700 may include any non-transitorycomputer readable medium or machine readable medium, such as an optical,magnetic or semiconductor storage. Storage medium 700 may store varioustypes of computer executable instructions, such as instructions toimplement logic flow 600. Examples of a computer readable or machinereadable storage medium may include any tangible media capable ofstoring electronic data, including volatile memory or non-volatilememory, removable or non-removable memory, erasable or non-erasablememory, writeable or re-writeable memory, and so forth. Examples ofcomputer executable instructions may include any suitable type of code,such as source code, compiled code, interpreted code, executable code,static code, dynamic code, object-oriented code, visual code, and thelike. The examples are not limited in this context.

FIG. 8 illustrates an embodiment of a device 1100. In some embodiments,device 1100 may be configured or arranged for either providing power orreceiving power via wireless or inductive power transfer. Device 1100may implement, for example, apparatus 500/800, storage medium 700/1000and/or a logic circuit 1170. The logic circuit 1170 may include physicalcircuits to perform operations described for apparatus 500/800. As shownin FIG. 8, device 1100 may include a radio interface 1110, basebandcircuitry 1120, and computing platform 1130, although embodiments arenot limited to this configuration.

The device 1100 may implement some or all of the structure and/oroperations for apparatus 500/800, storage medium 700/1000 and/or logiccircuit 1170 in a single computing entity, such as entirely within asingle device. The embodiments are not limited in this context.

Radio interface 1110 may include a component or combination ofcomponents adapted for transmitting and/or receiving single carrier ormulti-carrier modulated signals (e.g., including complementary codekeying (CCK) and/or orthogonal frequency division multiplexing (OFDM)symbols and/or single carrier frequency division multiplexing (SC-FDMsymbols) although the embodiments are not limited to any specificover-the-air interface or modulation scheme. Radio interface 1110 mayinclude, for example, a receiver 1112, a transmitter 1116 and/or afrequency synthesizer 1114. Radio interface 1110 may include biascontrols, a crystal oscillator and/or one or more antennas 1118-f. Inanother embodiment, radio interface 1110 may use externalvoltage-controlled oscillators (VCOs), surface acoustic wave filters,intermediate frequency (IF) filters and/or RF filters, as desired. Dueto the variety of potential RF interface designs an expansivedescription thereof is omitted.

Baseband circuitry 1120 may communicate with radio interface 1110 toprocess receive and/or transmit signals and may include, for example, ananalog-to-digital converter 1122 for down converting received signals, adigital-to-analog converter 1124 for up converting signals fortransmission. Further, baseband circuitry 1120 may include a baseband orphysical layer (PHY) processing circuit 1126 for PHY link layerprocessing of respective receive/transmit signals. Baseband circuitry1120 may include, for example, a processing circuit 1128 for mediumaccess control (MAC)/data link layer processing. Baseband circuitry 1120may include a memory controller 1132 for communicating with MACprocessing circuit 1128 and/or a computing platform 1130, for example,via one or more interfaces 1134.

In some embodiments, PHY processing circuit 1126 may include a frameconstruction and/or detection component, in combination with additionalcircuitry such as a buffer memory, to construct and/or deconstructcommunication frames (e.g., containing subframes). Alternatively or inaddition, MAC processing circuit 1128 may share processing for certainof these functions or perform these processes independent of PHYprocessing circuit 1126. In some embodiments, MAC and PHY processing maybe integrated into a single circuit.

Computing platform 1130 may provide computing functionality for device1100. As shown, computing platform 1130 may include a processingcomponent 1140. In addition to, or alternatively of, baseband circuitry1120 of device 1100 may execute processing operations or logic forapparatus 500/800, storage medium 700/1000, and logic circuit 1170 usingthe processing component 1140. Processing component 1140 (and/or PHY1126 and/or MAC 1128) may comprise various hardware elements, softwareelements, or a combination of both. Examples of hardware elements mayinclude devices, logic devices, components, processors, microprocessors,circuits, processor circuits, circuit elements (e.g., transistors,resistors, capacitors, inductors, and so forth), integrated circuits,application specific integrated circuits (ASIC), programmable logicdevices (PLD), digital signal processors (DSP), field programmable gatearray (FPGA), memory units, logic gates, registers, semiconductordevice, chips, microchips, chip sets, and so forth. Examples of softwareelements may include software components, programs, applications,computer programs, application programs, system programs, softwaredevelopment programs, machine programs, operating system software,middleware, firmware, software modules, routines, subroutines,functions, methods, procedures, software interfaces, application programinterfaces (API), instruction sets, computing code, computer code, codesegments, computer code segments, words, values, symbols, or anycombination thereof. Determining whether an example is implemented usinghardware elements and/or software elements may vary in accordance withany number of factors, such as desired computational rate, power levels,heat tolerances, processing cycle budget, input data rates, output datarates, memory resources, data bus speeds and other design or performanceconstraints, as desired for a given example.

Computing platform 1130 may further include other platform components1150. Other platform components 1150 include common computing elements,such as one or more processors, multi-core processors, co-processors,memory units, chipsets, controllers, peripherals, interfaces,oscillators, timing devices, video cards, audio cards, multimediainput/output (I/O) components (e.g., digital displays), power supplies,and so forth. Examples of memory units may include without limitationvarious types of computer readable and machine readable storage media inthe form of one or more higher speed memory units, such as read-onlymemory (ROM), random-access memory (RAM), dynamic RAM (DRAM),double-data-rate DRAM (DDRAM), synchronous DRAM (SDRAM), static RAM(SRAM), programmable ROM (PROM), erasable programmable ROM (EPROM),electrically erasable programmable ROM (EEPROM), flash memory, polymermemory such as ferroelectric polymer memory, ovonic memory, phase changeor ferroelectric memory, silicon-oxide-nitride-oxide-silicon (SONOS)memory, magnetic or optical cards, an array of devices such as redundantarray of independent disks (RAID) drives, solid state memory devices(e.g., USB memory, solid state drives (SSD) and any other type ofstorage media suitable for storing information.

Computing platform 1130 may further include a network interface 1160. Insome embodiments network interface 1160 may include logic and/orfeatures to support network interfaces operated in compliance with oneor more wireless or wired technologies such as those described above forestablishing a communication link through a low power wirelesscommunication interface.

Device 1100 may include a PTU or a PRU and may be, for example, userequipment, a computer, a personal computer (PC), a desktop computer, alaptop computer, a notebook computer, a netbook computer, a tabletcomputer, an ultra-book computer, a smart phone, a wearable computingdevice, embedded electronics, a gaming console. Accordingly, functionsand/or specific configurations of device 1100 described herein, may beincluded or omitted in various embodiments of device 1100, as suitablydesired.

Embodiments of device 1100 may be implemented using single input singleoutput (SISO) architectures. However, certain implementations mayinclude multiple antennas (e.g., antennas 1118-f) for transmissionand/or reception using adaptive antenna techniques for beamforming orspatial division multiple access (SDMA) and/or using multiple inputmultiple output (MIMO) communication techniques.

The components and features of device 1100 may be implemented using anycombination of discrete circuitry, application specific integratedcircuits (ASICs), logic gates and/or single chip architectures. Further,the features of device 1100 may be implemented using microcontrollers,programmable logic arrays and/or microprocessors or any combination ofthe foregoing where suitably appropriate. It is noted that hardware,firmware and/or software elements may be collectively or individuallyreferred to herein as “logic” or “circuit.”

It should be appreciated that the example device 1100 shown in the blockdiagram of FIG. 8 may represent one functionally descriptive example ofmany potential implementations. Accordingly, division, omission orinclusion of block functions depicted in the accompanying figures doesnot infer that the hardware components, circuits, software and/orelements for implementing these functions would be necessarily bedivided, omitted, or included in embodiments.

Some examples may be described using the expression “in one example” or“an example” along with their derivatives. These terms mean that aparticular feature, structure, or characteristic described in connectionwith the example is included in at least one example. The appearances ofthe phrase “in one example” in various places in the specification arenot necessarily all referring to the same example.

Some examples may be described using the expression “coupled”,“connected”, or “capable of being coupled” along with their derivatives.These terms are not necessarily intended as synonyms for each other. Forexample, descriptions using the terms “connected” and/or “coupled” mayindicate that two or more elements are in direct physical or electricalcontact with each other. The term “coupled,” however, may also mean thattwo or more elements are not in direct contact with each other, but yetstill co-operate or interact with each other.

It is emphasized that the Abstract of the disclosure is provided willallow the reader to quickly ascertain the nature of the technicaldisclosure. It is submitted with the understanding that it will not beused to interpret or limit the scope or meaning of the claims. Inaddition, in the foregoing Detailed Description, it can be seen thatvarious features are grouped together in a single example for thepurpose of streamlining the disclosure. This method of disclosure is notto be interpreted as reflecting an intention that the claimed examplesrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter lies in lessthan all features of a single disclosed example. Thus the followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separate example. In the appended claims,the terms “including” and “in which” are used as the plain-Englishequivalents of the respective terms “comprising” and “wherein,”respectively. Moreover, the terms “first,” “second,” “third,” and soforth, are used merely as labels, and are not intended to imposenumerical requirements on their objects.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

Examples

One example may be an apparatus including circuitry for a powertransmitting unit (PTU) capable of inductively or wirelesslytransferring power to one or more power receiving units (PRUs), areceiving component for execution by the circuitry to receive anadvertisement (ADV) packet with a forward signaling support bit and anempty ID field from a first PRU, a detecting component for detecting theADV and determining a message transmission time, a modulation componentfor starting a power modulation after a predetermined timing delay, anda transmitting component for transmitting an encoded message to thefirst PRU, wherein the receiving component receives an ADV with forwardsignaling support bit and an ID extracted from the first PRU, and thedetecting component detects the ADV with a matching ID and sends aconnection request to the first PRU. The message may be modulated usingbinary phase shift keying (BPSK). The message may be further modulatedusing differential modulation or differential CDMA/convolutional codemodulation. A magnitude of the message may be about 10% or less thanthat of a charging signal. The modulation may be a fixed voltage swing.

Another example may be a method of communication between a powertransmitting unit (PTU) capable of inductively or wirelesslytransferring power to one or more power receiving units (PRUs), themethod including the steps of a first PRU sending an advertisementpacket (ADV) with a forward signaling support bit and an empty ID field,a first PTU detecting the ADV and determining a message transmissiontime, the first PTU starting a power modulation after a predeterminedtiming delay, the first PRU decoding a message sent by the first PTU,the first PRU sending an ADV with forward signaling support bit and anID extracted from the message, and the first PTU detecting the ADV witha matching ID and sending a connection request to the first PRU. Themessage may be modulated using binary phase shift keying (BPSK). Themessage may be further modulated using differential modulation ordifferential CDMA/convolutional code modulation. A magnitude of themessage may be about 10% or less than that of a charging signal. Themodulation may be a fixed voltage swing.

Another example may be a machine readable medium including a pluralityof instructions that in response to being executed by circuitry for apower transmitting unit (PTU) capable of inductively or wirelesslytransferring power to one or more power receiving units (PRUs) causesthe circuitry to receive an advertisement (ADV) packet with a forwardsignaling support bit and an empty ID field from a first PRU, detectingthe ADV and determining a message transmission time, starting a powermodulation after a predetermined timing delay, and transmitting anencoded message to the first PRU, receiving an ADV with forwardsignaling support bit and an ID extracted from the first PRU, anddetecting the ADV with a matching ID for sending a connection request tothe first PRU. The message may be modulated using binary phase shiftkeying (BPSK). The message may be further modulated using differentialmodulation or differential CDMA/convolutional code modulation. Amagnitude of the message may be about 10% or less than that of acharging signal. The modulation may be a fixed voltage swing.

Another example may be an apparatus including circuitry for a powerreceiving unit (PRU) to inductively or wirelessly receive power from apower transmitting unit (PTU), a sending component for execution by thecircuitry to send an advertisement (ADV) packet with a forward signalingsupport bit and an empty ID field to a PTU, a receiving component forreceiving an encoded message from the PTU, wherein the sending componentsends an ADV with forward signaling support bit and an ID extracted fromthe message, and the PTU detects the ADV with a matching ID and sends aconnection request to the PRU. The message may be modulated by the PTUusing binary phase shift keying (BPSK). The message may be furthermodulated by the PTU using differential modulation or differentialCDMA/convolutional code modulation. A magnitude of the message may beabout 10% or less than that of a charging signal. The modulation may bea fixed voltage swing.

Another example may be a machine readable medium including a pluralityof instructions that in response to being executed by circuitry for apower receiving unit (PRU) causes the circuitry to send an advertisement(ADV) packet with a forward signaling support bit and an empty ID fieldto a power transmitting unit (PTU), receive an encoded message from thePTU, decode the encoded message and extract an ID in the encodedmessage, and send an ADV with forward signaling support bit and an IDextracted from the message, wherein the PTU detects the ADV with amatching ID and sends a connection request to the PRU. The message maybe modulated by the PTU using binary phase shift keying (BPSK). Themessage may be further modulated by the PTU using differentialmodulation or differential CDMA/convolutional code modulation. Amagnitude of the message may be about 10% or less than that of acharging signal. The modulation may be a fixed voltage swing.

What is claimed is:
 1. A method, comprising: causing to send a shortbeacon; detecting, based at least in part on the short beacon, acharging load; causing to send a long beacon after detecting thecharging load; determining that an advertisement (ADV) packet isreceived from a first PRU, wherein the ADV packet comprises an emptyidentifier field and a signaling support bit; causing to send aconnection request to the first PRU based at least in part on detectingthe empty identifier field and the signaling support bit in the ADVpacket, wherein the connection request is sent within a predeterminedperiod of time; and causing to transition to a power state to charge thefirst PRU, responsive to a timing delay after the ADV packet isreceived.
 2. The method of claim 1, wherein the identifier fieldcomprises a unique identifier of the first PRU.
 3. The method of claim1, wherein detecting the charging load comprises detecting a change inimpedance of the charging load.
 4. An article comprising anon-transitory machine-accessible medium having stored thereoninstructions that, when executed by one or more machines, cause the oneor more machines to perform operations comprising: causing to transmit ashort beacon; detecting, based at least in part on the short beacon, acharging load; causing to transmit a long beacon after detecting thecharging load; determining an advertisement (ADV) packet received from afirst PRU, wherein the ADV packet comprises an empty identifier fieldand a signaling support bit; causing to send a connection request to thefirst PRU based at least in part on detecting the empty identifier fieldand the signaling support bit in the ADV packet, wherein the connectionrequest is sent within a predetermined period of time; and causing totransition to a power state to charge the first PRU, responsive to atiming delay after the ADV packet is received.
 5. The article of claim4, wherein the identifier field comprises a unique identifier of thefirst PRU.
 6. The article of claim 4, wherein detecting the chargingload comprises detecting a change in impedance of the charging load. 7.An article comprising a non-transitory machine-accessible medium havingstored thereon instructions that, when executed by one or more machines,cause the one or more machines to perform operations comprising:determining a long beacon carrying power was received from a powertransmitting unit (PTU); causing to energize a communication interfaceusing the power received via the long beacon; generating anadvertisement (ADV) packet, wherein the ADV packet comprises an emptyidentifier field and a signaling support bit; causing to send the ADVpacket; identifying a connection request received from the PTU, whereinthe connection request is received within a predetermined period oftime; and causing to transition to a power state, to receive power fromthe PTU for charging, responsive to a timing delay after the ADV packetis sent.
 8. The article of claim 7, wherein causing to energize thecommunication interface comprises energizing a low power communicationinterface.
 9. The article of claim 8, wherein energizing the low powercommunication interface comprises energizing a Bluetooth Low Energy(BLE) interface.